The error message told that the request that you made don't match any operation of Microsoft Planner connector. This error is a predefined error for built-in steps.
I have made a test on my side and don't have the issue that you mentioned. Please check the configuration of your Microsoft Planner service. In addition, please consider take a try to re-create a new connection to Planner connector and check if the issue is solved.
More details about the predefined errors for built-in steps, please check the following article: